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Students Work on Safer Weed Control Device

The kinder, gentler weed whacker hopes to be an alternative to herbicides, which can harm pets and children, and organic versions that take longer to work and are less effective.

Three University of Dayton engineering students have been working on a kinder, gentler weed whacker as an alternative to herbicides, which can harm pets and children, and organic versions that take longer to work and are less effective.

Bridget Hamblin, Fred Schulkers and Joe Swinko worked with Oregon-based thermal weed control specialist Sunburst Inc. on a hairdryer of sorts to whack weeds.

The device produces concentrated doses of propane-generated heat on unwanted growth. Exposing vegetation to temperatures at least 140 degrees for about two seconds disables normal plant functions and prevents or stunts future growth.

"Other organic methods may take longer and also involve foam or other chemicals," Hamblin said. "Weed burners on the market now introduce smoke into the air and are not really environmentally safe."

The students' tests showed weeds wilted after two sprays in about four days.

"The effect of our product is relatively immediate compared to store-bought herbicides," said Sunburst's Bill Clemmens. "Compared to other products that use water and propane, we use less of both. Plus, you can't use a lot of water in places prone to water shortages."

The students' device, the first in Sunburst's line that is hand-held, will be suitable for household use or in tight spots with large crowds such as amusement parks. Sunburst's equipment includes pushcarts, trailers and attachments to heavy machinery or trucks.

The students are hoping to add to Sunburst's line of equipment with their device, which is as light as a gas-powered weed trimmer and cheaper than accumulated costs of annual herbicide purchases. After the initial cost of equipment, the only recurring cost is a propane canister, which lasts a little more than 90 minutes on full use. The device utilizes all conventional parts so it is easy to manufacture and assemble.

Sunburst still has some additional work to do before sending the device to market but Clemmens said, "We are incredibly close compared to where we were at the beginning of the semester."

"I've enjoyed watching the development of this," Clemmens said. "This is an opportunity for the students to take something conceptual and make it concrete. This will be extremely instructive if they want to work in industry."

The UD students' work was part of UD's Design and Manufacturing Clinic, which provides learning opportunities and, according to Engineering Times, "hones engineering creativity." Since 1996, student teams have completed more than 200 projects for more than 70 companies, according to Phil Doepker, the clinic's coordinator.

Hamblin is happy to finally apply what she learned in the classroom and have something her group can call its own.

"Plus, this is our first experience with vendors," she added. "That was interesting, and it's another thing we can say we have done when we hit the workplace."

Usually, a team of three or four upper-level undergraduate students, along with a faculty mentor, work on a sponsor's project for four months. The students address issues relating to product design, environmental issues and cost estimation, among others.

In turn, the sponsor provides an industry mentor to guide the students from the company's perspective. Companies also provide between $1,500 and $4,000 to cover clinic costs, travel, laboratory use and general administrative expenses.

For self-proclaimed tinkerers like Swinko, a little fun is included, too.

"I think a few other teams were jealous we were able to have a hands-on project while they worked on theoretical stuff," said Swinko, who graduated last weekend with Schulkers. "It was fun to watch how quickly this developed in a semester."